connector 1
connector 2

The BNC connector operates very well up to about 4 GHz; beyond that it tends to radiate electromagnetic energy. The BNC can accept flexible cables with with a diameter of up to 0.25" (6.35 mm) and characteristic impedance of 75Ω. MFG Amphenol (NYSE:APH)

1/2 inch Super Flex Helix Cable, 50Ω Foam Dielectric Coax Cable Part Number LDF4-50A for Andrew Corporation (Insertion Loss 5.97 dB per 100 Ft @ 5.8 GHz) MFG Commscope (NYSE:COMM)

The TNC is brass body per QQ-B-626. Solder on connector, 50Ω operates up to 11 GHz. Temperature range -65 C to +165 (connector only). Insulation Resistance is 5x10^3 MΩ, RF Leakage is > 60dB at 3 GHz